On Wed, Oct 31, 2012 at 01:46:43PM +0100, Kay Sievers wrote: > On Wed, Oct 31, 2012 at 1:24 PM, Karel Zak <kzak@xxxxxxxxxx> wrote: > > On Tue, Oct 30, 2012 at 11:03:59PM +0000, Matt Burgess wrote: > > >> 1) mount(8) > >> > >> /dev/root on / type ext3 (rw,relatime,data=ordered) > > > > I see (Fedora 17, util-linux 2.21.2) > > > /dev/sda4 on / type ext4 (rw,relatime,data=ordered) > > We see that only if we use an initramfs. In case the kernel mounts the > fs directly and internally, there is /dev/root showing up. Ah, good point. > >> Nope, that's not /dev/sda3. And what is /dev/root anyway? There's no > >> such node under /dev here. > > The kernel creates that node in its own 'rootfs' names filesystem, the > parent of the entire filesystem mount tree; but this is never visible > anywhere in the real system, and never was. > > Ideally, the kernel would be fixed to use the root= string, and not > invent a name that does never exist. Yes, hmm... I'll try to improve libmount to convert /dev/root to something usable. > > if I good remember there was symlink in some distributions > > Some distributions created /dev/root with udev rules which have been > composed at bootup. We dropped all that, because it is logic backwards > and nothing on the system should rely on /dev/root being available. > Modern filesystems like btrfs do not follow the "there is a single > device below that mountpoint logic". I guess it's still necessary to use some magic btrfs ioctls to get info about the filesystem, right? It would be nice to have something in /sys/fs/btrfs. -- Karel Zak <kzak@xxxxxxxxxx> http://karelzak.blogspot.com -- To unsubscribe from this list: send the line "unsubscribe util-linux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
